RT Journal Article ID 22fe8b892b7577d8 A1 Webb, Ralph L. A1 Ermis, Kemal T1 Effect of Hydraulic Diameter on Condensation of R-134A in Flat, Extruded Aluminum Tubes JF Journal of Enhanced Heat Transfer JO JEH(T) YR 2001 FD 2001-04-01 VO 8 IS 2 SP 77 OP 90 AB This paper addresses the effect of hydraulic diameter on single-phase and condensation heat transfer and pressure gradient for R-I34a in multi-port flat extruded aluminum tubes. The hydraulic diameter range of the four tubes tested is between 0.44 and 1.56 mm. This work is believed to provide condensation data on the smallest hydraulic diameters reported in the literature. The modified Wilson plot method was used to determine the heat transfer coefficient for water-side flow in the annulus. The data span 300−1000kg/m2-s mass velocity and approximately 15-to-90% vapor qualities. The condensation coefficient and pressure gradient increases with decreasing hydraulic diameter for all tubes. The effect of hydraulic diameter on condenser design and operation is also discussed. The ability of existing correlations to predict the single-phase and condensation coefficients are evaluated. PB Begell House LK https://www.dl.begellhouse.com/journals/4c8f5faa331b09ea,7abfef2f6d11049a,22fe8b892b7577d8.html